1976 step in the Pacific climate: forty environmental changes between 1968-1975 and 1977-1984

• Main Authors: Ebbesmeyer, Curtis C., Cayan, Daniel R., McLain, Douglas R., Nichols, Frederic H., Peterson, David H., Redmond, Kelly T.
• Format: Conference Object
• Language: English
• Published: 1991
• Subjects: Atmospheric Sciences; Ecology; Oceanography; Earth Sciences; Environment; Bering Strait; Pacific
• Online Access: http://aquaticcommons.org/4562/; http://aquaticcommons.org/4562/1/EbbesmeyerEtal_1990_ProcPacCLIM7th_pp115-126.pdf

Examination of 40 time series of multidisciplinary environmental variables from the Pacific Ocean and the Americas, collected in 1968 to 1984, demonstrated the remarkable consistency of a major climate-related, step-like change in 1976. To combine the 40 variables (e.g., air and water temperatures, Southern Oscillation, chlorophyll, geese, salmon, crabs, glaciers, atmospheric dust, coral, carbon dioxide, winds, ice cover, Bering Strait transport) into a single time series, standard variants of individual annual values (subtracting the mean and dividing by a standard deviation) were averaged. Analysis of the resulting time series showed that the single step in 1976, separating the 1968-1975 period from the 1977-1984 period, accounted for 89% of variance within the composite time series. Apparently, one of the Earth's large ecosystems occasionally undergoes large abrupt shifts.